Lung cells will be dispersed and fractionated using rosette and gradient techniques. Anti-mouse lung cell sera will be made specific for different cell types through appropriate absorptions. Specific sera and lectins will be used to study the effect of specific binding at the cell-surface on measurable parameters of the particular cell's physiology. Using specific antisera or lectins, single antigenic species will be precipitated from solubilized cell membranes and characterized biochemically.